Myocardial injury in patients with acute ischemic stroke detected by cardiovascular magnetic resonance imaging

BACKGROUND

Patients with acute ischemic stroke (AIS) are at high risk of adverse cardiovascular events. Until now, the burden of myocardial injury derived from cardiovascular magnetic resonance imaging (CMR) has not been established in this population.

METHODS

Patients with AIS underwent CMR at 3 Tesla within 120 h after the index stroke as part of a prospective, single-center study. Patients with persistent atrial fibrillation were excluded. Morphology and function of both cardiac chambers and atria were assessed applying SSFP cine. Myocardial tissue differentiation was based on native and contrast-enhanced imaging including late gadolinium enhancement (LGE) after 0.15 mmol/kg gadobutrol for focal fibrosis and parametric T2- and T1-mapping for diffuse findings. To detect myocardial deformation global longitudinal (GLS), circumferential (GCS) and radial (GRS) strain was measured applying feature tracking. Cardiac troponin was measured using a high-sensitivity assay (99th percentile upper reference limit 14 ng/L). T2 mapping values were compared with 20 healthy volunteers.

RESULTS

CMR with contrast media was successfully performed in 92 of 115 patients (mean age 74 years, 40% female, known myocardial infarction 6%). Focal myocardial fibrosis (LGE) was detected in 31 of 92 patients (34%) of whom 23/31 (74%) showed an ischemic pattern. Patients with LGE were more likely to have diabetes, prior myocardial infarction, prior ischemic stroke, and to have elevated troponin levels compared to those without. Presence of LGE was accompanied by diffuse fibrosis (increased T1 native values) even in remote cardiac areas as well as reduced global radial, circumferential and longitudinal strain values. In 14/31 (45%) of all patients with LGE increased T2-mapping values were detectable.

CONCLUSIONS

More than one-third of patients with AIS have evidence of focal myocardial fibrosis on CMR. Nearly half of these changes may have acute or subacute onset. These findings are accompanied by diffuse myocardial changes and reduced myocardial deformation. Further studies, ideally with serial CMR measurements during follow-up, are required to establish the impact of these findings on long-term prognosis after AIS.

CMR assessment of right ventricular remodeling after transcatheter therapy for severe tricuspid regurgitation

Funding Acknowledgements

Type of funding sources: Private hospital(s). Main funding source(s): Helios Clinical Research Institute

Background/Introduction

Patients with severe tricuspid regurgitation (TR) are characterized from severe dilatation and negative remodeling of the right heart chambers causing functional right ventricular (RV) failure and increased mortality and morbidity. The transcatheter tricuspid edge-to-edge repair (TTVR) is a new treatment option associated with symptom improvement and reduced hospitalization. The cardiac magnetic resonance imaging (CMRI) remains the gold standard for evaluating the right ventricular morphology and function and could be a useful in assessing the RV reverse remodeling after TTVR.  The Tricuspid Regurgitation REgistry (TRuE) is an ongoing national prospective register of patients with severe TR that aims to identify morphofunctional parameters of the right heart chambers related to improve outcomes after TTVR.

Purpose

The present is a subanalysis of patients with serial CMRI examinations recruited in the ongoing prospective TRuE registry.

Methods

After excluding patients with intracardiac RV leads, seven patients (age 70 ±12 years) with completed thirty-day follow up were included in the present analysis. Retrospective gated steady state free precession cine images were acquired in the long and short-axis views covering the entirety of both ventricles. Aortic and pulmonary flow data were acquired with a flow-sensitive gradient echo sequence. Assessment of left ventricular (LV) and RV volumes was performed manually in the short-axis cine images (Circle Cardiovascular Imaging, Calgary, Alberta, Canada). The TR fraction was calculated as: ({total RV stroke volume (SV) – total pulmonary forward flow}/total RVSV) × 100. All volumes and flow measurements were indexed for body surface area and expressed in ml/m2. The ratio between the diameter of pulmonary artery (PA) and ascending aorta (AA) was used as indirect measurement of pulmonary arterial hypertension (PAH). CMRI parameters assessing TR quantification, RV morphology and function were analyzed at baseline and follow-up with Fisher´s test or paired t-test.

Results

At thirty days there was a significant reduction of the TR fraction (45% to 20%, p < 0.001), RV dilatation (RV-end diastolic volume (EDV): 106 ± 12ml/m2 to 86 ± 9.4ml/m2, p = 0.002, RV- end sistolic volume (ESV):55 ± 6.5 to 43 ± 6.6ml, p = 0.003) and improvement of function (RVEF: 47 ± 3.6 to 53 ± 2.4 %, p = 0.006). On the left heart side, there was an improvement of LV filling, with increased LVEDV and LVESV and of the LVSV (36 ± 5.3 to 41 ± 3.7ml/m2, p = 0.040), causing an improvement of the cardiac index (2.2 ± 0.9 l/min/m2 to 2.9 ± 0.7 l/min/m2; p = 0.019. Furthermore, the PA/AA ratio improved significantly (0.91 ± 0.15 to 0.81 ± 0.14, p = 0.006).

Conclusion

TTVR is associated with positive reverse remodeling of the RV with reduction of dilatation, PAH and function improvement.

Stratifying the prognostic capability of cardiovascular magnetic resonance in severe aortic stenosis: a machine learning approach

Background

Cardiovascular magnetic resonance (CMR) demonstrates promise in improving patient risk stratification in aortic stenosis (AS). We explored whether machine learning might provide further insights into the prognostic capability of CMR parameters.

Methods

Severe AS patients (n=440) undergoing AVR were prospectively enrolled across 10 international sites, and CMR performed prior to AVR. A machine learning prediction model using a random survival forest (RSF) was trained with 29 variables, including 13 CMR, 4 echocardiography, and 12 clinical parameters, using post-AVR mortality as an outcome. The impact of the important variables on the outcome (partial dependency) was examined.

Results

The most predictive CMR parameters in the RSF model were the extracellular volume fraction (ECV%), followed by right ventricular ejection fraction (RVEF), late gadolinium enhancement (LGE%), and indexed left ventricular end-diastolic volume (LVEDVi). Regarding the partial effects, the predicted mortality increased strongly once the ECV% exceeded 26.5% (Figure 1A). The LGE% was associated with an increased risk of mortality, which reached a plateau beyond the level of 2% (Figure 1C). There were U-shaped relationships between mortality and both RVEF and LVEDVi, with the lowest mortality seen at RVEF 70% and LVEDVi 68ml/m2 (Figure 1B, D). These trends of predicted outcomes by each variable were verified in the Kaplan-Meier curves and Cox analyses (Table). In both Cox and RSF models, the predictability was substantially increased when these four CMR parameters were added to conventional clinical risk factors. An AS-CMR risk score comprised of these four parameters presented a stepwise increase in mortality with increasing adverse CMR features (p<0.001).

Conclusions

Our machine learning analysis using RSF has identified ECV%, RVEF, LGE%, and LVEDVi as key prognostic markers in severe AS with a nonlinear influence of each parameter on mortality post-AVR.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): This study was supported by grants from the Korean Health Technology R & D Project, Ministry of Health, Welfare & Family Affairs, Republic of Korea (HI16C0225 and HI15C0399) and the National Institute for Health Research (NIHR) infrastructure at Leeds.

Guidelines for training in cardiovascular magnetic resonance (CMR)

These "Guidelines for training in Cardiovascular Magnetic Resonance" were developed by the Certification Committee of the Society for Cardiovascular Magnetic Resonance (SCMR) and approved by the SCMR Board of Trustees.

Branched-chain amino acid catabolism rather than amino acids plasma concentrations is associated with diet-induced changes in insulin resistance in overweight to obese individuals

BACKGROUND & AIMS

3-Hydroxyisobutyrate (3-HIB), a catabolic intermediate of the BCAA valine, which stimulates muscle fatty acid uptake, has been implicated in the pathogenesis of insulin resistance. We tested the hypothesis that circulating 3-HIB herald insulin resistance and that metabolic improvement with weight loss are related to changes in BCAAs and 3-HIB.

METHODS AND RESULTS

We analyzed plasma and urine in 109 overweight to obese individuals before and after six months on hypocaloric diets reduced in either carbohydrates or fat. We calculated the homeostasis model assessment index (HOMA-IR) and whole body insulin sensitivity from oral glucose tolerance tests and measured intramyocellular fat by magnetic resonance spectroscopy. BCAAs and 3-HIB plasma concentrations were inversely related to insulin sensitivity but not to intramyocellular fat content at baseline. With 7.4 ± 4.5% weight loss mean BCAA and 3-HIB plasma concentrations did not change, irrespective of dietary macronutrient content. Individual changes in 3-HIB with 6-month diet but not BCAAs were correlated to the change in whole body insulin sensitivity and HOMA-IR independently of BMI changes.

CONCLUSIONS

3-HIB relates to insulin sensitivity but is not associated with intramyocellular fat content in overweight to obese individuals. Moreover, changes in 3-HIB rather than changes in BCAAs are associated with metabolic improvements with weight loss. Registration number for clinical trials: ClinicalTrials.gov Identifier: NCT00956566.

Branched-chain and aromatic amino acids, insulin resistance and liver specific ectopic fat storage in overweight to obese subjects

BACKGROUND & AIMS

Amino acids may interfere with insulin action, particularly in obese individuals. We hypothesized that increased circulating branched-chain and aromatic amino acids herald insulin resistance and ectopic fat storage, particularly hepatic fat accumulation.

METHODS AND RESULTS

We measured fasting branched-chain and aromatic amino acids (tryptophan, tyrosine, and phenylalanine) by mass spectrometry in 111 overweight to obese subjects. We applied abdominal magnetic resonance imaging and spectroscopy to assess adipose tissue distribution and ectopic fat storage, respectively. Plasma branched-chain amino acids concentrations were related to insulin sensitivity and intrahepatic fat independent from adiposity, age and gender, but not to abdominal adipose tissue or intramyocellular fat.

CONCLUSIONS

In weight stable overweight and obese individuals, branched-chain amino acid concentrations are specifically associated with hepatic fat storage and insulin resistance.

[Cardiovascular ultrahigh field magnetic resonance imaging : challenges, technical solutions and opportunities]

CLINICAL/METHODICAL ISSUE

This involves high spatial resolution cardiac imaging with ultrahigh magnetic fields (7 T) and clinically acceptable image quality.

STANDARD RADIOLOGICAL METHODS

Cardiovascular magnetic resonance imaging (MRI) at a field strength of 1.5 T using a spatial resolution of (2 × 2 × 6-8) mm(3).

METHODICAL INNOVATIONS

Cardiac MRI at ultrahigh field strength makes use of multitransmit/receive radiofrequency (RF) technology and development of novel technology that utilizes the traits of ultrahigh field MRI.

PERFORMANCE

Enhanced spatial resolution which is superior by a factor of 6-10 to what can be achieved by current clinical cardiac MRI. The relative spatial resolution (pixels per anatomical structure) comes close to what can be accomplished by current cardiac MRI in small rodents.

ACHIEVEMENTS

Feasibility studies demonstrate the gain in spatial resolution at 7.0 T due to the sensitivity advantage inherent to ultrahigh magnetic fields.

PRACTICAL RECOMMENDATIONS

Please stay tuned and please put further weight behind the solution of the remaining technical problems of cardiac MRI at 7.0 T.

[Cardiomyopathies and myocarditis]

CLINICAL ISSUE

Cardiomyopathies and myocarditis are frequently challenging in clinical practice regarding differentiation, risk stratification and treatment strategy. There are various disease entities which often affect young or middle-aged adults and the course is variable from asymptomatic and irrelevant for prognosis to sudden cardiac death or severe heart failure even at an early age. Making the right diagnosis is therefore fundamental to correctly identify affected patients and to initiate treatment steps in time.

STANDARD TREATMENT

Whereas causal treatment options exist for some forms of cardiomyopathy, the majority of patients receives standard heart failure and device therapy but others require lifelong careful monitoring.

DIAGNOSTIC WORK-UP

The diagnosis of cardiomyopathy is mainly based on the cardiac phenotype; therefore, non-invasive imaging is very important. Cardiovascular magnetic resonance has become the gold standard to assess cardiomyopathy as it combines functional information (e.g. wall motion) with myocardial tissue analysis (e.g. fibrosis and edema) and in some cases it can replace invasive endomyocardial biopsies.

PERFORMANCE

The importance of cardiovascular magnetic resonance to assess cardiomyopathy is based on several aspects: accurate analysis of cardiac dimensions and function, non-invasive tissue analysis to make the diagnosis (e.g. myocarditis), estimation of prognosis by non-invasive tissue analysis, high reproducibility for accurate follow-up examinations, potential for technical improvements (e.g. quantification of extracellular volume fraction by T1 mapping).

ACHIEVEMENTS

In all types of cardiomyopathy, cardiovascular magnetic resonance has a major impact on the differential diagnosis, risk stratification and treatment. In some entities the appropriate clinical use is already confirmed by evidence (e.g. myocarditis) and in others there are first encouraging results that indicate the future potential (e.g. risk stratification in hypertrophic cardiomyopathy).

PRACTICAL RECOMMENDATIONS

Cardiovascular magnetic resonance has evolved as the gold standard to assess cardiomyopathy as it provides both functional and morphological information. It is recommended to use this technique in a comprehensive approach to achieve complete work-up of affected patients.

4D flow magnetic resonance imaging in bicuspid aortic valve disease demonstrates altered distribution of aortic blood flow helicity

PURPOSE

Changes in aortic geometry or presence of aortic valve (AoV) disease can result in substantially altered aortic hemodynamics. Dilatation of the ascending aorta or AoV abnormalities can result in an increase in helical flow.

METHODS

4D flow magnetic resonance imaging was used to test the feasibility of quantitative helicity analysis using equidistantly distributed 2D planes along the entire aorta. The evaluation of the method included three parts: (1) the quantification of helicity in 12 healthy subjects, (2) an evaluation of observer variability and test-retest reliability, and (3) the quantification of helical flow in 16 patients with congenitally altered bicuspid AoVs.

RESULTS

Helicity quantification in healthy subjects revealed consistent directions of flow rotation along the entire aorta with high clockwise helicity in the aortic arch and an opposite rotation sense in the ascending and descending aorta. The results demonstrated good scan-rescan and inter- and intraobserver agreement of the helicity parameters. Helicity quantification in patients revealed a significant increase in absolute peak relative helicity during systole and a considerably greater heterogeneous distribution of mean helicity in the aorta.

CONCLUSION

The method has the potential to serve as a reference distribution for comparisons of helical flow between healthy subjects and patients or between different patient groups.

Determinants of exercise-induced fat oxidation in obese women and men

Endurance training at an intensity eliciting maximal fat oxidation may have a beneficial effect on body weight and glucose metabolism in obese patients. However, the exercise intensity at which maximal fat oxidation occurs and the factors limiting fat oxidation are not well studied in this population. Obese, otherwise healthy men (n=38) and women (n=91) performed an incremental exercise test up to exhaustion on a cycle ergometer. Substrate oxidation was estimated using indirect calorimetry. Magnetic resonance tomography and spectroscopy were conducted to assess body fat distribution and intramyocellular fat content. We determined the exercise intensity at which maximal body fat oxidation occurs and assessed whether body composition, body fat distribution, intramyocellular fat content, or oxidative capacity predict exercise-induced fat oxidation. Maximal exercise-induced fat oxidation was 0.30+/-0.02 g/min in men and 0.23+/-0.01 g/min in women (p<0.05). Exercise intensity at the maximum fat oxidation was 42+/-2.2% VO (2 max) in men and 43+/-1.7% VO (2 max) in women. With multivariate analysis, exercise-induced fat oxidation was related to fat-free mass, percent fat mass, and oxidative capacity, but not to absolute fat mass, visceral fat, or intramyocellular fat content. We conclude that in obese subjects the capacity to oxidize fat during exercise appears to be limited by skeletal muscle mass and oxidative capacity rather than the availability of visceral or intramyocellular fat.

Improvement of fractional flow reserve and collateral flow by treatment with external counterpulsation (Art.Net.-2 Trial)

BACKGROUND

Arteriogenesis (collateral artery growth) is nature's most efficient rescue mechanism to overcome the fatal consequences of arterial occlusion or stenosis. The goal of this trial was to investigate the effect of external counterpulsation (ECP) on coronary collateral artery growth.

MATERIALS AND METHODS

A total of 23 patients (age 61 +/- 2.5 years) with stable coronary artery disease and at least one haemodynamic significant stenosis eligible for percutaneous coronary intervention were prospectively recruited into the two study groups in a 2 : 1 manner (ECP : control). One group (ECP group, n = 16) underwent 35 1-h sessions of ECP in 7 weeks. In the control group (n = 7), the natural course of collateral circulation over 7 weeks was evaluated. All patients underwent a cardiac catheterization at baseline and after 7 weeks, with invasive measurements of the pressure-derived collateral flow index (CFIp, primary endpoint) and fractional flow reserve (FFR).

RESULTS

In the ECP group, the CFIp (from 0.08 +/- 0.01 to 0.15 +/- 0.02; P < 0.001) and FFR (from 0.68 +/- 0.03 to 0.79 +/- 0.03; P = 0.001) improved significantly, while in the control group no change was observed. Only the ECP group showed a reduction of the Canadian Cardiovascular Society (CCS, P = 0.008) and New York Heart Association (NYHA, P < 0.001) classification.

CONCLUSION

In this study, we provide direct functional evidence for the stimulation of coronary arteriogenesis via ECP in patients with stable coronary artery disease. These data might open a novel noninvasive and preventive treatment avenue for patients with non-acute vascular stenotic disease.

Myocardial tissue characterization in systemic lupus erythematosus: value of a comprehensive cardiovascular magnetic resonance approach

Systemic lupus erythematosus (SLE) is a multi-organ inflammatory disorder mainly affecting women and is associated with high cardiovascular morbidity and mortality. We tested the utility of a comprehensive cardiovascular magnetic resonance approach to assess myocardial involvement and to determine its relation to disease activity in SLE patients. We studied 20 SLE patients (19 females, 35 ± 10 years) and 13 healthy volunteers (nine females, 28 ± 11 years). Classification followed the criteria of the American College of Rheumatology and assessment of SLE activity was based on the European Consensus Lupus Activity Measurement index. Cardiovascular magnetic resonance (CMR) was performed on a 1.5T scanner and included the following sequences: steady-state free precession, T2-weighted, early and late T1-weighted after gadolinium-DTPA injection. Ejection fraction was not significantly different between groups (controls: 63 ± 6, inactive SLE: 67 ± 7, active SLE 64 ± 8; P = 0.003 for all groups). In contrast, relative T2 ratio (myocardium to skeletal muscle) was significantly higher in active SLE than in the other groups (controls: 1.7 ± 0.3, inactive: 1.8 ± 0.2, active: 2.1 ± 0.2; P = 0.003). Similarly, early enhancement ratio was significantly higher in active SLE (controls: 2.4 ± 1.4, inactive: 2.8 ± 1.1, active: 4.5 ± 2.0, P = 0.39). Both relative T2 and early enhancement ratios significantly correlated with disease activity. Intramural foci of late enhancement were observed in three of eight patients (all with active SLE). Of the five patients with no late enhancement, only one had active disease. An imaging approach combining T2-weighted, early and late enhancement imaging is a useful tool to assess possible myocardial involvement in SLE. CMR parameters of global myocardial involvement correlate well with disease activity, but not with usual clinical signs as summarized in a cardiac score.

Biochemical and bioimaging markers for risk assessment and diagnosis in major cardiovascular diseases: a road to integration of complementary diagnostic tools

This report from the first International Course on Integrated Biomarkers, Biochemical and Bioimaging Endpoints in Cardiovascular Diagnosis, Prevention, Therapy and Drug Development provides the basis for optimizing diagnostic, prognostic and therapeutic information in four areas of cardiovascular medicine: primary prevention of cardiovascular diseases, acute coronary syndromes, heart failure and stroke. Risk stratification and treatment strategies can be refined and enhanced through integration of bioimaging and biochemical markers to characterize sub-clinical and clinical atherosclerosis. For the integrative approach to be useful, each of the biomarkers must be validated and cost-effective. Clinical decision is the primary level of integration and is based on clinical evaluation and the use of a combination of bioimaging and biochemical markers. The decision to initiate preventive or therapeutic intervention must take into account the factors affecting the levels of expression of the biomarker and the potential input the biomarker has on metabolic processes or modulation of other biomarkers. The optimal approach to intervention must take into consideration the risk-benefit and cost-effectiveness ratios.

Nuclear magnetic resonance for the assessment of the effects of alcohol septal ablation in hypertrophic cardiomyopathy

Alcohol ablation of the interventricular septum is a well-established method of treatment in hypertrophic obstructive cardiomyopathy (HOCM). The extent of ablation-induced iatrogenic infarction is usually assessed by the use of echocardiography. The role of nuclear magnetic resonance (NMR) in this setting has not yet been well established. In this report we describe five patients with HOCM who underwent alcohol septal ablation and subsequent NMR evaluation. The usefulness of NMR in these patients is discussed and comparison with echocardiographic results is presented.

Safety of implantable coronary stents during 1H-magnetic resonance imaging at 1.0 and 1.5 T

The safety of most available implantable intracoronary stents during magnetic resonance imaging (MRI) has not been sufficiently tested. Minor, but possibly clinically significant, increases in temperature have not been excluded. We measured temperature changes of 14 different stents clinically in use or currently tested for release on the world market. Stents were examined in 1.0- and 1.5-T MR scanners with multiple sequences used in routine cardiac and thoracic MRI examinations ("clinical worst case") and after implantation of the stents into the coronary arteries of excised pig hearts (1.5-T scanner only). We used a highly sensitive infrared camera with a thermal resolution of 10 mK and did not see significant heating of any stent during the examinations. We conclude that MRI is safe in patients with the currently available intracoronary stents.

Magnetic resonance planimetry of the vena contracta as a new approach to assessment of stenotic heart valves: an in vitro study

Exact determination of the orifice area in stenotic valve disease is essential to guide therapy. With the standard imaging methods, the orifice area has to be calculated by empirically-derived formulas, which may be susceptible to changes in hemodynamic status, leading to wrong therapeutic decisions. We tested the ability of magnetic resonance imaging (MRI) to quantify the orifice area by planimetry of the proximal vena contracta (PVC) in an idealized, constant-flow model in a 1.0-T tomograph (Siemens Magnetom Expert). There was a close correlation of the PVC area in MRI and the true orifice area (r2 = 0.985), and agreement of the methods as measured by the Bland-Altman test was significant with a low systematic error of -0.02 cm2. We conclude that MRI planimetry of the PVC in stenotic valves in a constant-flow model may be used to reliably measure the orifice area.

Subclinical cardiotoxic effects of anthracyclines as assessed by magnetic resonance imaging-a pilot study

BACKGROUND

Anthracyclines are potent chemotherapeutics burdened by their cardiotoxicity. So far no marker to detect early cardiac damage exists. We tested the ability of magnetic resonance imaging (MRI) to show early changes in myocardial signal and cardiac function after anthracycline therapy.

METHODS

Twenty-two patients with normal cardiac function were investigated by MRI before and 3 and 28 days after anthracycline chemotherapy. Contrast enhanced fast spin echo images were obtained to characterize myocardial enhancement. Left ventricular ejection fraction was measured by MRI in contiguous short-axis planes.

RESULTS

All patients remained clinically stable. Ejection fraction decreased from 67.8% +/- 1.4% to 58.9% +/- 1.9% after 28 days (P < .05). The relative myocardial contrast enhancement increased from 3.8 +/- 0.4 to 6.9 +/- 1.1 (P < .01). An increase of the enhancement of >5 on day 3 compared with baseline predicted a significant loss of ejection fraction at 28 days (67.5% +/- 2.8% to 51.4% +/- 5.6%, mean difference 16.1% +/- 6.6%; P < .05), whereas an increase of +5 was not associated with a significant loss of ejection fraction (67.6% +/- 1.7% to 62.5% +/- 1.4%, mean difference 4.1% +/- 2.6%; P not significant).

CONCLUSIONS

MRI detects early changes in myocardial contrast and slightly deteriorating cardiac function in patients receiving anthracyclines. Larger patient cohorts and longer follow-up are needed to evaluate MRI as a predictor for anthracycline cardiotoxicity.

Measurement of left ventricular dimensions and function in patients with dilated cardiomyopathy

Studies on medical therapy in heart failure are focused on changes of left ventricular (LV) dimensions and function. These changes may be small, requiring a large study group. We measured LV parameters (LV volumes, LV ejection fraction (LV-EF), and left ventricular mass (LVM)) with two-dimensional echocardiography (2D-echo) and magnetic resonance imaging (MRI) in 50 patients. Based on the difference between the measurements, we determined the variance of the results and calculated the sample sizes needed to detect changes of baseline values. For the calculated and measured parameters we found significant differences between the two techniques: LV-EF and LVM were higher in 2D-echo, and LV dimensions were comparable. The sample size to detect relevant changes from baseline with MRI was significantly (P < 0.01) smaller than in 2D-echo. We conclude that MRI is superior in clinical studies on left ventricular dimensional and functional changes, since measurements are more reproducible and the required sample size is substantially smaller, thereby reducing costs.

Visualization of cardiac involvement in patients with systemic sarcoidosis applying contrast-enhanced magnetic resonance imaging

Contrast-enhanced MRI may serve as a sensitive noninvasive tool for the detection and follow-up of myocardial involvement in patients with systemic sarcoidosis.

Magnetic resonance imaging in patients with cardiomyopathies: when and why

Cardiac magnetic resonance imaging (MRI) is a noninvasive tool which is able to diagnose and differentiate cardiomyopathies in a single study. The assessment of essential information such as alterations of myocardial and ventricular geometry and function is possible with a high degree of accuracy and reproducibility, based on a small inter- and intraobserver variability. Thus, very small morphological and functional changes in different types of cardiomyopathy are detectable, thereby enabling the cardiologist to increase the safety of therapeutic decisions. Furthermore, MRI bears the potential to characterize tissue transformation in the different types of myocardial affections including ischemic, toxic, infiltrative or inflammatory forms.

The value of magnetic resonance imaging of the left ventricular outflow tract in patients with hypertrophic obstructive cardiomyopathy after septal artery embolization

BACKGROUND

We tested the value of magnetic resonance imaging (MRI) in the follow-up of patients with hypertrophic obstructive cardiomyopathy after septal artery embolization. MRI provides a noninvasive visualization of transplanar turbulent flow in order to quantify left ventricular outflow tract obstruction.

METHODS AND RESULTS

We followed 10 patients who were treated with septal artery embolization for 12 months. We used gradient echo sequences to document continuous improvement of the outflow tract area and T1- and T2-weighted spin echo sequences to visualize myocardial infarction. A continuous, but not linear, improvement of the outflow tract area occurred after septal artery embolization during the 12-month follow-up period. The improvement of the outflow tract area correlated well with the amelioration of symptoms (r(2)=0.86).

CONCLUSIONS

We conclude that MRI reliably detects the degree of obstruction in patients with hypertrophic obstructive cardiomyopathy. This modality may be especially useful for follow-up after septal artery embolization.